Printers have long suffered from portability problems, with the majority of printers primarily for desktop use and typically weighing dozens of pounds. Even as computing devices have moved towards more lightweight systems, such as smart phones, laptop computers, notebook and sub-notebook computers, and tablet computers, printing from these devices frequently requires connecting, either wirelessly or physically, to a desktop printer. As a result, use cases for these printers are limited.
Manufacturers have attempted to extend portability to printers, though current implementations suffer from various defects. For example, continuous-roll black and white direct thermal printers, such as those used in portable credit card readers and point-of-sale terminals utilize a thermal printing head that applies heat to a dye impregnated in a printing medium, activating the dye or color-forming chemical to create black and/or gray pixels. The resulting prints are frequently low-resolution and relatively unstable, fading and/or darkening over time, and as a result are useful only for temporary prints, such as receipts.
Conversely, continuous-roll thermal wax transfer printers or dye-diffusion thermal transfer printers use separate donor and receiver materials, allowing color-on-color printing with very high stability. Prints typically do not fade unless damaged through friction. However, color choices are fixed (e.g. black lettering on a white medium, or red lettering on a yellow medium), and switching between colors requires switching cassettes or cartridges. As a result, multicolor images or labels cannot be created.
Multicolor thermal printers produce full-color, stable prints, and may be relatively small. However, in typical implementations, the printing medium is delivered in predetermined dimensions, such as 3 inches by 5 inches, or 5 inches by 7 inches, limiting potential uses compared to a continuous-roll printer. Other printing methods such as ink jet printers and laser printers are typically larger and heavier, making them unavailable for portable printing, and suffer from problems such as ink cartridges drying out before the user has consumed the maximum number of prints possible.
Furthermore, as typically befits their roles as printers for other computing devices, most printers lack user interfaces for editing images or text to be printed. Conversely, the few that include keypads such as handheld label printers, typically allow only alphanumeric entry, and have formatting constraints such as fixed sizes, fonts, or text orientations.